Such an absorbent inner sole is already known from the document FR 87 09 708.
In addition, various makers offer inner linings or "inner soles" which are not well adapted to the problem of heating up of the feet as a result of excessive sweating, their aim being above all to obtain a warmer shoe, or height compensation between the shoe and the foot. These essentially flat inner soles made of natural products such as skins, leather, cork, textiles or synthetic products, are made of a single material or of combined materials.
The average life of these types of linings is equivalent to the life of the shoe for the most durable ones; comfort and hygiene are reduced even if some linings are washable. In addition, the materials used become either weak or more and more rigid, depending on their nature.
The principle drawbacks are as follows:
premature ageing through chemical burning of the materials constituting the shoe, PA1 rapid degradation of the qualities of comfort of the walking elements such as socks, stockings, or tights, due in particular to the accumulation of sweat, PA1 more or less restricting treatments dispensed on broken skin, blisters, and fungal infections, PA1 emanation of an offensive odour relating to sweat. PA1 the outer sealing film is very fine, made of synthetic material, PA1 the hygienic pad of natural materials is highly flexible and lightly packed, PA1 hygienic additives and treatment additives are added to the flexible pad, PA1 the inner film, a few hundredths of a millimeter thick, is pierced, PA1 the films are glued or welded to one another at their edges. PA1 the two films are glued or welded by point-like traverses made in the hygienic pad. PA1 the inner film is pierced with "lanced" holes in the shape of micro-funnels, or cut by small slits, single or combined into stars, produced without removal of material. PA1 the insert contains products which in the presence of sweat stiffen the insert, comprising pellets or reactive surfaces which gradually change colour, depending on the concentration of sweat. PA1 the insert is extended onto the sides and the top of the foot, either by the pad or simply by one or both films, shaped and then glued or welded to one another completely or at various points, or by separate upper and vamp parts also joined by gluing or welding to the base insert, or it is provided with a textile or a film covering the rest of the foot, the ankle and the calf in order to provide an ankle sock and a sock. PA1 the pad is based on sphagnum or loofah. PA1 point-like aeration passages are provided in the sides and on the top of the foot. PA1 pre-glued adhesive areas, protected by paper before being installed, are situated on the outer film in order to be applied, without spoiling, to the insole and/or to the sides of the shoe, or situated on the inner film of a mule or a ballerina, in the direction of the top and of certain lateral areas of the bare or sock-covered foot. PA1 the insert includes a thin film, covering the inner film, for the continuous manufacture of an assembly formed of the outer sealing film, the hygienic pad, the inner film, itself optionally provided with another film, to form a sheet which is cut out to the shape of the insert to be manufactured, the cut-out portions being welded at the same time in order to provide the disposable insert.